Particular attention is directed to the U.S. Holtermann Pat. No. 4,122,652 and the U.S. Poehlman Pat. No. 4,053,980, each of those patents being assigned to the assignee of the present invention.
Attention is also directed to the U.S. Tombers Pat. No. 3,967,438; the U.S. Zurek Pat. No. 3,908,344; the U.S. Zurek Pat. No. 3,897,678; and the U.S. Shriver Pat. No. 3,871,159.
Attention is further directed to the U.S. Dowdle Pat. No. 2,985,992; the U.S. Meylink Pat. No. 3,613,815; and the U.S. Kamlukin Pat. No. 3,731,472.
Attention is also directed to the U.S. Hansen Pat. No. 3,386,545; the U.S. Culbertson Pat. No. 3,841,453; and the U.S. Carlson Pat. No. 2,366,594.